[davidgto]

I have a 65 GTO with original suspension. I would think springs are weak. I have a set of 15x7 plain steel wheels I want to mount and run dog dish.

With weak springs in mind, what size tire can I run with the tallest and the most wide being the preference.

[Cardo]

215/65/15 in the front and 215/70/15 in the rear. There's about 1 inch difference in the diameter, but if you go any bigger or wider in the front they almost always catch the fender in the rear on a turn. In the rear you can run a 245/60/15 if you want something fatter in the rear in a similar overall diameter. I'm currently running the 215's all the way around, but had the 245's on the rear a couple of months ago. I just didn't care for the look, but otherwise they were fine.

[i82much]

i have run 275/60r15 rear and 225/70r14 front on oem rally 2 wheels for many years, but cannot say how weak springs would affect that fitment.

[The Champ]

Assuming your 15x7's are 4.25" BS, this is my 64 GTO with 235/60/15 front and 255/60/15 rear.

My GTO has the wider (by about 1") 12 bolt rear. If you have the correct 10 bolt rear you have even more room.

I eventually was able to convert my front drum brakes to disc which widened the front track and did in certain situations cause a light rub with the 235's. But when I did the front disc changeover I also lowered the car which was a contributing factor.

[davidgto]

Thanks fellows so much.

[johnta1]

Assuming your 15x7's are 4.25" BS

You mean 4.75" BS?

[The Champ]

Originally Posted by johnta1

You mean 4.75" BS?

No.

Standard 15x7 black steel wheel BS was 4.25".

4.75" BS and I could have run 245/60/15's up front and 275/60/15's out back - even with my disc brakes and wider 12 bolt rear.

[post toastie]

245 60 15 front 275 60 15 rear on a 65 tempest 4 door

[Lemans64]

Originally Posted by post toastie

245 60 15 front 275 60 15 rear on a 65 tempest 4 door

But with what rim width and with what backspace?? Thought we could only fit a 275 in rear with an 8 wheel and 5 backspace? Or maybe a 7 wide and 4.5 backspace?

[ZeGermanHam]

Originally Posted by Lemans64

But with what rim width and with what backspace??

That's what I want to know, too. I've never heard of someone fitting a 245 section width tire on the front of one of these cars with a typical 15" Pontiac Rally II wheel as shown in his photos.

[post toastie]

they are stock 15x7 4 :25 backspace the tires are big for the 65, I would have to say that 235 60 15 and 255 60 15 would be a better fit.

[ZeGermanHam]

Originally Posted by post toastie

I would have to say that 235 60 15 and 255 60 15 would be a better fit.

Is that another way of saying that the 245 fronts rub?

[post toastie]

They don't rub while driving normally but the driver side when getting the spring to compress the tire will touch the top of the fender while turning to the left. I might be able to align the car on the frame to fix it or a different offset wheel ? The tires are tall and wide. The right rear rubs on the inside if I am {hanging a corner}. surprisingly it is decent to drive normally around on.

[post toastie]

My 14 x 7 inch slot mags with 225 70 will rub the driver side fender when the spring compresses also while turning the same way the 245 60 15 does .

[post toastie]

tire size calculator https://tiresize.com/calculator/